#index3 {
  opacity: 0;
}
.bg_size {
  background-size: 100% 100%;
  background-repeat: no-repeat;
}
#index3 .main {
  position: relative;
}
#index3 .main .main_bg {
  width: 7.5rem;
  height: 13.34rem;
  background: url(../img/index3/背景.png);
  background-size: 100% 100%;
  background-repeat: no-repeat;
}
#index3 .main .content {
  position: absolute;
  top: 25%;
  left: 26%;
}
#index3 .main .title {
  width: 3.61rem;
  height: 1.08rem;
  background: url(../img/index3/活动介绍.png);
  background-size: 100% 100%;
  background-repeat: no-repeat;
}
#index3 .main .content ul {
  margin-top: 0.2rem;
  display: flex;
  flex-direction: column;
  list-style-type: none;
  font-size: 0.24rem;
}
#index3 .main .content ul li {
  width: 3.61rem;
  margin-bottom: 0.5rem;
  line-height: 0.45rem;
  transition: opacity 1s;
  opacity: 0;
}
#index3 .btn {
  width: 4.35rem;
  height: 2.02rem;
  position: absolute;
  background: url(../img/index2/我要猜灯谜.png);
  background-size: 100% 100%;
  background-repeat: no-repeat;
  bottom: 8%;
  left: -81%;
  transition: left 4s;
  z-index: 3;
}
#index3 .bottom {
  width: 7.5rem;
  height: 2.71rem;
  background: url(../img/index2/bottom.png);
  background-position: 0 100%;
  background-size: 100% 100%;
  background-repeat: no-repeat;
  position: absolute;
  bottom: 0;
  z-index: 2;
}
